HDFS-5948. TestBackupNode flakes with port in use error. (Contributed by Haohui Mai)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1568532 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5949. New Namenode UI when trying to download a file, the browser doesn't know the file name.Contributed by Haohui Mai

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1568536 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5716. Allow WebHDFS to use pluggable authentication filter. Contributed by Haohui Mai

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1568547 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5953. TestBlockReaderFactory fails in trunk. (Akira Ajisaka via wang)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1568568 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5749. Web UI does not show up during the period of loading FSImage. (Contributed by Haohui Mai)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1568578 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5698. Update CHANGES.txt to move breakdown of tasks to correct release

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1568582 13f79535-47bb-0310-9956-ffa450edef68